Sheets using petroleum resins such as polyvinyl chloride (PVC) are widely used in various building structures such as houses, mansions, apartments, offices, stores, and the like.
Such sheets are produced by extrusion or calendering of resins such as polyvinyl chloride (PVC). Raw materials for these sheets are exclusively derived from limited resources such as crude oil. It is thus anticipated that depletion of petroleum resources will lead to various problems related to the supply of raw materials.
As interest in environmental issues is recently growing in importance, polyvinyl chloride (PVC) sheets are problematic in that they are likely to emit harmful substances and create an environmental burden when discarded.
To solve such problems, a polylactic acid (PLA) resin extracted and synthesized from plant resources has attracted attention as a material capable of replacing petroleum based resins in recent years.
Environmentally friendly sheets using such a PLA resin are disclosed in prior documents including Korean Patent Laid-open Publication No. 10-2008-0067424.
However, a PLA resin-based sheet has a drawback in that the sheet clings to a processing apparatus upon thermal lamination, or is not easily stacked in multiple layers due to lack of viscoelasticity upon processing at high temperature, as compared with sheets prepared from an existing PVC resin.